Kerberos utility functions for GENSEC
- Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004
+ Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "system/kerberos.h"
-#include "system/time.h"
-#include "system/network.h"
#include "auth/kerberos/kerberos.h"
-#include "auth/auth.h"
+#include "auth/credentials/credentials.h"
+#include "auth/credentials/credentials_proto.h"
+#include "auth/credentials/credentials_krb5.h"
+#include "auth/kerberos/kerberos_credentials.h"
+#include "auth/kerberos/kerberos_util.h"
-struct ccache_container {
+struct principal_container {
struct smb_krb5_context *smb_krb5_context;
- krb5_ccache ccache;
-} ccache_container;
+ krb5_principal principal;
+ const char *string_form; /* Optional */
+};
-static int free_ccache(void *ptr) {
- struct ccache_container *ccc = ptr;
+static krb5_error_code free_principal(struct principal_container *pc)
+{
/* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
- krb5_cc_close(ccc->smb_krb5_context->krb5_context, ccc->ccache);
+ krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
return 0;
}
+
+static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
+ const char *princ_string,
+ struct smb_krb5_context *smb_krb5_context,
+ krb5_principal *princ,
+ const char **error_string)
+{
+ int ret;
+ struct principal_container *mem_ctx;
+ if (princ_string == NULL) {
+ *princ = NULL;
+ return 0;
+ }
+
+ ret = krb5_parse_name(smb_krb5_context->krb5_context,
+ princ_string, princ);
+
+ if (ret) {
+ (*error_string) = smb_get_krb5_error_message(
+ smb_krb5_context->krb5_context,
+ ret, parent_ctx);
+ return ret;
+ }
+
+ mem_ctx = talloc(parent_ctx, struct principal_container);
+ if (!mem_ctx) {
+ (*error_string) = error_message(ENOMEM);
+ return ENOMEM;
+ }
+
+ /* This song-and-dance effectivly puts the principal
+ * into talloc, so we can't loose it. */
+ mem_ctx->smb_krb5_context = talloc_reference(mem_ctx,
+ smb_krb5_context);
+ mem_ctx->principal = *princ;
+ talloc_set_destructor(mem_ctx, free_principal);
+ return 0;
+}
+
+/* Obtain the principal set on this context. Requires a
+ * smb_krb5_context because we are doing krb5 principal parsing with
+ * the library routines. The returned princ is placed in the talloc
+ * system by means of a destructor (do *not* free). */
+
+krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx,
+ struct cli_credentials *credentials,
+ struct smb_krb5_context *smb_krb5_context,
+ krb5_principal *princ,
+ enum credentials_obtained *obtained,
+ const char **error_string)
+{
+ krb5_error_code ret;
+ const char *princ_string;
+ TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
+ *obtained = CRED_UNINITIALISED;
+
+ if (!mem_ctx) {
+ (*error_string) = error_message(ENOMEM);
+ return ENOMEM;
+ }
+ princ_string = cli_credentials_get_principal_and_obtained(credentials,
+ mem_ctx,
+ obtained);
+ if (!princ_string) {
+ *princ = NULL;
+ return 0;
+ }
+
+ ret = parse_principal(parent_ctx, princ_string,
+ smb_krb5_context, princ, error_string);
+ talloc_free(mem_ctx);
+ return ret;
+}
+
+/* Obtain the principal set on this context. Requires a
+ * smb_krb5_context because we are doing krb5 principal parsing with
+ * the library routines. The returned princ is placed in the talloc
+ * system by means of a destructor (do *not* free). */
+
+static krb5_error_code impersonate_principal_from_credentials(
+ TALLOC_CTX *parent_ctx,
+ struct cli_credentials *credentials,
+ struct smb_krb5_context *smb_krb5_context,
+ krb5_principal *princ,
+ const char **error_string)
+{
+ return parse_principal(parent_ctx,
+ cli_credentials_get_impersonate_principal(credentials),
+ smb_krb5_context, princ, error_string);
+}
+
/**
* Return a freshly allocated ccache (destroyed by destructor on child
* of parent_ctx), for a given set of client credentials
*/
- NTSTATUS kinit_to_ccache(TALLOC_CTX *parent_ctx,
- struct cli_credentials *credentials,
- struct smb_krb5_context *smb_krb5_context,
- krb5_ccache *ccache,
- const char **ccache_name)
+ krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
+ struct cli_credentials *credentials,
+ struct smb_krb5_context *smb_krb5_context,
+ struct tevent_context *event_ctx,
+ krb5_ccache ccache,
+ enum credentials_obtained *obtained,
+ const char **error_string)
{
krb5_error_code ret;
const char *password;
- char *ccache_string;
+ const char *self_service;
+ const char *target_service;
time_t kdc_time = 0;
- struct ccache_container *mem_ctx = talloc(parent_ctx, struct ccache_container);
+ krb5_principal princ;
+ krb5_principal impersonate_principal;
+ int tries;
+ TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
+ krb5_get_init_creds_opt *krb_options;
if (!mem_ctx) {
- return NT_STATUS_NO_MEMORY;
+ (*error_string) = strerror(ENOMEM);
+ return ENOMEM;
}
- password = cli_credentials_get_password(credentials);
-
- /* this string should be unique */
- ccache_string = talloc_asprintf(mem_ctx, "MEMORY:%s_%s",
- cli_credentials_get_principal(credentials, mem_ctx),
- generate_random_str(mem_ctx, 16));
-
- ret = krb5_cc_resolve(smb_krb5_context->krb5_context, ccache_string, ccache);
+ ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ, obtained, error_string);
if (ret) {
- DEBUG(1,("failed to generate a new krb5 keytab (%s): %s\n",
- ccache_string,
- error_message(ret)));
talloc_free(mem_ctx);
- return NT_STATUS_INTERNAL_ERROR;
+ return ret;
}
- mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
- mem_ctx->ccache = *ccache;
+ if (princ == NULL) {
+ (*error_string) = talloc_asprintf(credentials, "principal, username or realm was not specified in the credentials");
+ talloc_free(mem_ctx);
+ return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
+ }
+
+ ret = impersonate_principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &impersonate_principal, error_string);
+ if (ret) {
+ talloc_free(mem_ctx);
+ return ret;
+ }
+
+ self_service = cli_credentials_get_self_service(credentials);
+ target_service = cli_credentials_get_target_service(credentials);
+
+ password = cli_credentials_get_password(credentials);
+
+ /* setup the krb5 options we want */
+ if ((ret = krb5_get_init_creds_opt_alloc(smb_krb5_context->krb5_context, &krb_options))) {
+ (*error_string) = talloc_asprintf(credentials, "krb5_get_init_creds_opt_alloc failed (%s)\n",
+ smb_get_krb5_error_message(smb_krb5_context->krb5_context,
+ ret, mem_ctx));
+ talloc_free(mem_ctx);
+ return ret;
+ }
+
+ /* get the defaults */
+ krb5_get_init_creds_opt_set_default_flags(smb_krb5_context->krb5_context, NULL, NULL, krb_options);
+
+ /* set if we want a forwardable ticket */
+ switch (cli_credentials_get_krb_forwardable(credentials)) {
+ case CRED_AUTO_KRB_FORWARDABLE:
+ break;
+ case CRED_NO_KRB_FORWARDABLE:
+ krb5_get_init_creds_opt_set_forwardable(krb_options, FALSE);
+ break;
+ case CRED_FORCE_KRB_FORWARDABLE:
+ krb5_get_init_creds_opt_set_forwardable(krb_options, TRUE);
+ break;
+ }
+
+ /*
+ * In order to work against windows KDCs even if we use
+ * the netbios domain name as realm, we need to add the following
+ * flags:
+ * KRB5_INIT_CREDS_NO_C_CANON_CHECK;
+ * KRB5_INIT_CREDS_NO_C_NO_EKU_CHECK;
+ */
+ krb5_get_init_creds_opt_set_win2k(smb_krb5_context->krb5_context,
+ krb_options, true);
+
+ tries = 2;
+ while (tries--) {
+ struct tevent_context *previous_ev;
+ /* Do this every time, in case we have weird recursive issues here */
+#ifdef SAMBA4_USES_HEIMDAL
+ ret = smb_krb5_context_set_event_ctx(smb_krb5_context, event_ctx, &previous_ev);
+ if (ret) {
+ talloc_free(mem_ctx);
+ return ret;
+ }
+#endif
+ if (password) {
+ if (impersonate_principal) {
+#ifdef SAMBA4_USES_HEIMDAL
+ ret = kerberos_kinit_s4u2_cc(
+ smb_krb5_context->krb5_context,
+ ccache, princ, password,
+ impersonate_principal,
+ self_service, target_service,
+ krb_options, NULL, &kdc_time);
+#else
+ talloc_free(mem_ctx);
+ (*error_string) = "INTERNAL error: s4u2 ops "
+ "are not supported with MIT build yet";
+ return EINVAL;
+#endif
+ } else {
+ ret = kerberos_kinit_password_cc(
+ smb_krb5_context->krb5_context,
+ ccache, princ, password,
+ target_service,
+ krb_options, NULL, &kdc_time);
+ }
+ } else if (impersonate_principal) {
+ talloc_free(mem_ctx);
+ (*error_string) = "INTERNAL error: Cannot impersonate principal with just a keyblock. A password must be specified in the credentials";
+ return EINVAL;
+ } else {
+ /* No password available, try to use a keyblock instead */
+
+ krb5_keyblock keyblock;
+ const struct samr_Password *mach_pwd;
+ mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
+ if (!mach_pwd) {
+ talloc_free(mem_ctx);
+ (*error_string) = "kinit_to_ccache: No password available for kinit\n";
+ krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
+#ifdef SAMBA4_USES_HEIMDAL
+ smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
+#endif
+ return EINVAL;
+ }
+ ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
+ ENCTYPE_ARCFOUR_HMAC,
+ mach_pwd->hash, sizeof(mach_pwd->hash),
+ &keyblock);
+
+ if (ret == 0) {
+ ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
+ princ, &keyblock,
+ target_service, krb_options,
+ NULL, &kdc_time);
+ krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
+ }
+ }
+
+#ifdef SAMBA4_USES_HEIMDAL
+ smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
+#endif
+
+ if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
+ /* Perhaps we have been given an invalid skew, so try again without it */
+ time_t t = time(NULL);
+ krb5_set_real_time(smb_krb5_context->krb5_context, t, 0);
+ } else {
+ /* not a skew problem */
+ break;
+ }
+ }
+
+ krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
+
+ if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
+ (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
+ cli_credentials_get_principal(credentials, mem_ctx),
+ smb_get_krb5_error_message(smb_krb5_context->krb5_context,
+ ret, mem_ctx));
+ talloc_free(mem_ctx);
+ return ret;
+ }
- talloc_set_destructor(mem_ctx, free_ccache);
- ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, *ccache,
- cli_credentials_get_principal(credentials, mem_ctx),
- password, NULL, &kdc_time);
-
/* cope with ticket being in the future due to clock skew */
if ((unsigned)kdc_time > time(NULL)) {
time_t t = time(NULL);
krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
}
- if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
- DEBUG(1,("kinit for %s failed (%s)\n",
- cli_credentials_get_principal(credentials, mem_ctx),
- smb_get_krb5_error_message(smb_krb5_context->krb5_context,
- ret, mem_ctx)));
- talloc_free(mem_ctx);
- return NT_STATUS_TIME_DIFFERENCE_AT_DC;
+ if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
+ ret = kinit_to_ccache(parent_ctx,
+ credentials,
+ smb_krb5_context,
+ event_ctx,
+ ccache, obtained,
+ error_string);
}
+
if (ret) {
- DEBUG(1,("kinit for %s failed (%s)\n",
- cli_credentials_get_principal(credentials, mem_ctx),
- smb_get_krb5_error_message(smb_krb5_context->krb5_context,
- ret, mem_ctx)));
+ (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
+ cli_credentials_get_principal(credentials, mem_ctx),
+ smb_get_krb5_error_message(smb_krb5_context->krb5_context,
+ ret, mem_ctx));
talloc_free(mem_ctx);
- return NT_STATUS_WRONG_PASSWORD;
+ return ret;
}
- *ccache_name = ccache_string;
+ talloc_free(mem_ctx);
+ return 0;
+}
+
+static krb5_error_code free_keytab_container(struct keytab_container *ktc)
+{
+ return krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
+}
- return NT_STATUS_OK;
+krb5_error_code smb_krb5_get_keytab_container(TALLOC_CTX *mem_ctx,
+ struct smb_krb5_context *smb_krb5_context,
+ krb5_keytab opt_keytab,
+ const char *keytab_name,
+ struct keytab_container **ktc)
+{
+ krb5_keytab keytab;
+ krb5_error_code ret;
+
+ if (opt_keytab) {
+ keytab = opt_keytab;
+ } else {
+ ret = krb5_kt_resolve(smb_krb5_context->krb5_context,
+ keytab_name, &keytab);
+ if (ret) {
+ DEBUG(1,("failed to open krb5 keytab: %s\n",
+ smb_get_krb5_error_message(
+ smb_krb5_context->krb5_context,
+ ret, mem_ctx)));
+ return ret;
+ }
+ }
+
+ *ktc = talloc(mem_ctx, struct keytab_container);
+ if (!*ktc) {
+ return ENOMEM;
+ }
+
+ (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
+ (*ktc)->keytab = keytab;
+ talloc_set_destructor(*ktc, free_keytab_container);
+
+ return 0;
}
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